For drifts generated by the cooling system, a controller with an integral policy is generally used, and it is not discussed in this paper. For microphonics vibrations generated by machinery, NANC[1]} techniques were demonstrated in the last decade at CMTB [2]} and CBETA [3]}. The advantage of this kind of controller is the capability of rejecting sinuisoidal disturbances without exciting mechanical modes of the cavity. Additionally, NANC is an adaptive controller, meaning that it is capable of self-correct its internal parameters against variations of the noise properties. Therefore such a controller was chosen to test microphonics rejection on LCLS-II cavities.
